one of the commenter john perez asked me about sound system in fedora 7, actually i have same problem like him, i can't have sound in mplayer when i view youtube video, but if i closed youtube website, i can play mplayer, the problem is i can't have multiple sound like before, i have to turn off another application that use sound system, anyway i found the solution to fixed this bug, from here..linuxquestions.org - multi application sound 1.just copy this code to /etc/asound.conf (as root)